You've got the perfect place, but you can't really spend a lot of cash to furnish it; this handy chart will help teach you how to decorate on a budget. Try the most obvious spots first like second-hand stores where you'll likely be able to snag an awesome couch or an amazing ottoman. Make sure to get there early to score the cream of the crop.
Next, set a realistic budget that you can afford to set aside for making your house a home. This doesn't need to be huge, but make sure to take all of your everyday expenses like food and transportation into account, so that you aren't left short. A great source for quality second-hand goods is freebie websites where people give away what they don't need or can't fit in their new place.